Redwood Stair Treads
Since Redwood falls into the softwood category, I don't recommend using it for stair treads. However, I've used plenty of Redwood for stair treads, on exterior decks, porches and patios. Even though it is a softer wood that scratches easily, most people just can't resist, having this incredible wood, around their homes.
Redwood can be expensive, so pay attention to what
you're ordering. For example, an 8 foot long, 2 x 4 construction
standard, piece of Redwood, might only cost $6, but a clear heart piece
of Redwood the same size, could cost over $25. In other words, there's a
big difference in price, between clear heart redwood and construction
Gluing = Great, Redwood is an excellent wood to glue together, however, I've actually seen the glue hold and actually pull a section of the other piece that it was glued to, away from it. In other words, the glue held, but the wood didn't, simply because it's soft.
Sanding = Excellent, as a matter of fact, it can be too easy to sand. Be extremely careful sanding Redwood, because it is a soft wood and can easily become damaged.
Staining = Good, Redwood will definitely absorb different kinds of stains, but I've never actually seen a piece of Redwood stained. Remember, if you're looking for a particular type of finish, make sure that you purchase the correct wood and stain. Last thing you want to end up with is using an expensive lumber, to produce a finished look to your stairway, that you could have acquired, without wasting your money.
Nailing = Excellent, it's one of the softest woods I've ever worked with and I can't think of one time, I've ever needed to pre-drill a hole. Construction standard Redwood, will have knots, running throughout the boards, however, clear heart redwood won't. Knots make it difficult to nail or screw your stair treads to the stringers.
Wear And Tear = Fair, like I said earlier, I wouldn't use Cedar for stair treads or risers, because it scratches easily.
Janka Hardness Scale = 480